Multicompartment sachets for delivering ingredients in washing machines in a sequential manner have been disclosed in the prior art.
GB No. 2 000 177B (Akzo) discloses a two-compartment sachet containing a phosphate free detergent composition based on sodium carbonate. A first compartment is bounded by a water-permeable wall and separated by a partition from a second compartment bounded by an impermeable wall; the partition wall is of material that disintegrates in the wash water. The contents of the second compartment are therefore not released until the contents of the first compartment have been leached out and the partition wall has disintegrated.
U.S. Pat. No. 4,410,441 (Davies et al/Lever Brothers Company) discloses another two-compartment sachet which differs from that of GB No. 2 000 177B in that the partition wall is of water-insoluble water-permeable material. Release of the contents of the second compartment is by leaching out through the porous partition after the contents of the first compartment have been delivered.
EP No. 143 476A (Akzo) discloses a sachet having two compartments, one being formed of water-permeable material or material that immediately disintegrates in water and the other being formed of water-impermeable non-disintegrating material and being sealed with a water-sensitive composition comprising an anionic and/or nonionic water-binding polymer, for example, polyvinyl pyrrolidone and a cationic polymeric adhesive, for example, polyethyleneimine. The first compartment releases its contents rapidly, while release from the second compartment is delayed by the slow opening of the water-sensitive seals.
EP No. 66 463B (Unilever) discloses an article for releasing an active material in a controlled manner, comprising two layers of sheet material (laminates each consisting of an outer porous layer and an inner plastics film layer) bonded together in a grid pattern to form an array of cells or compartments. The sheet material is pinholed for release of active material. If desired different compartments can contain different active material and can be pinholed to differing extents to allow release of different active material at different rates.